Various wireless communication technologies are being developed in accordance with advancement of information communication technologies. Wireless communication technologies may be generally classified into technologies using licensed bands and technologies using unlicensed bands (e.g. industrial-scientific-medical (ISM) band) according to bands used by respective technologies. Since a licensed band is exclusively used by a specific operator, the technology using the licensed band may provide better reliability, communication quality, etc. than that using an unlicensed band.
There exists, as a representative cellular communication technology using a licensed band, a Long Term Evolution (LTE) or LTE-Advanced standardized in a 3rd generation partnership project (3GPP). Thus, a base station or a user equipment (UE) supporting LTE or LTE-Advanced may transmit or receive signals through a licensed band. Also, there exists, as a representative wireless communication technology using an unlicensed band, a wireless local area network (WLAN) defined in IEEE 802.11. Thus, an access point or a station supporting the WLAN may transmit or receive signals through the unlicensed band.
Meanwhile, as mobile traffics are increasing explosively, additional licensed bands are required in order to process such the increasing mobile traffics through licensed bands. However, licensed bands are limited resources. Since a licensed band is obtained usually through an auction held among operators, astronomical investment may be demanded for obtaining an additional licensed band. In order to resolve the above-described problem, a method for providing LTE or LTE-Advanced services through a unlicensed band may be considered.
In the case that LTE or LTE-Advanced services are provided through the unlicensed band, transmission and reception of signals may occur discontinuously due to use of discontinuous resources. Also, if conventional scheduling methods defined for licensed bands are applied to the unlicensed band, scheduling of some resources may become impossible.
Meanwhile, this description on the related arts is written for understanding of the background of the present disclosure. Thus, information on other than conventional technologies, which are already known to those skilled in this technology domain to which the technologies of the present disclosure belong, may be included in this description.